[Cataplectic falls disclosing hypercalcemia].

Clinical manifestations of hypercalcaemic encephalopathy were heralded in three patients by isolated cataplexy-like falls without loss of consciousness. In one patient the falls with global hypotonia occurred every 5 to 10 seconds and were unaccompanied by changes in E.E.G. The falls disappeared after hypercalcaemia was corrected by excision of a parathyroid adenoma in two patients and by calcitonin injections in one. For this reason, there is little doubt that they were due to the hypercalcaemia, but their mechanism is poorly understood; it probably involves metabolic disturbances in the reticular systems of the brain stem. The connections between calcium metabolism and neuromediators in the brain stem are discussed.